Tons of spots on the river but unfortunately everybody in town and their brother hits them up. I know Red Bridge and the Pipe get pounded from first ice to ice out, River Road slough gets lots of action as well. Lake DuBay seems to turn into the dead sea after new years. If you are willing to drive, I highly recommend the Big Eau Pleine. Great action if you get on them, seem to bite better in the afternoon/night time. Lots of small glacial lakes out towards Amherst/Stockton that are worth checking out for some action. Mission Lake and Pike Lake in Marathon county are good options as well if you are willing to drive a little bit out of town.
